Tool shaft for a tool of the percussive and rotative type

ABSTRACT

A device on hand machine tools is suggested for the transmission of torque to percussion drilling tools in which at least two rotary driving grooves open out at the end of the tool shaft and strip-shaped rotary drivers of the tool shaft engage in these rotary driving grooves and include assigned flanks, which are at least approximately planar, and in which locking members are arranged in the tool receptacle and cooperate with two recesses in the tool shaft which are closed on both sides and lie diametrically opposite one another. In order to avoid incorrectly reversed insertion of tools with driving grooves which are worn out due to intensive wear, the latter are distributed along the circumference of the tool shaft in such a way that two rotary driving grooves can in no case lie diametrically opposite one another.

BACKGROUND OF THE INVENTION

The invention is related to a device on hand machine tools.

Such a device is already known from DE-PS 25 51 125. Tools constructedaccording to this patent are also usable in principle in toolreceptacles provided according to AT-PS 285 405, wherein the lockingelements applied in the latter engage in the recesses which are closedon both sides and arranged in the tool shaft outside the rotary drivinggrooves. The width and depth of the rotary driving grooves opening outat the end of the tool shaft are selected in such a way that they cannot receive the locking elements, and accordingly the tool can not beincorrectly inserted.

However, particularly in severe construction site operation, the rotarydriving grooves can become worn out after long use of the tool to suchan extent that the tool can unintentionally be inserted into the toolholder in a position in which the locking elements engage in the rotarydriving grooves. This brings about the risk that the machine may beunexpectedly disengaged from the tool when withdrawing the machine fromthe workpiece during operation, since the locking elements of the toolreceptacle can slide out of the rotary driving grooves, which are opentoward the end of the tool, in an unimpeded manner. This is particularlydangerous because when working with the machine the operator can notdetermine in certain cases that the tool is incorrectly inserted. Inthis case, the operator will only notice it--but in an entirelyunanticipated manner--when he withdraws the machine from the workpieceand the tool, which is possibly stuck in the workpiece, remains in thelatter. Since this separation of machine and tool is entirelyunanticipated by the operator, there is the danger that he will lose hisbalance when working on a ladder or scaffold, which brings about aconsiderable risk of accident.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a toolof the above-described percussive and rotative type which is safer tooperate than that currently available.

In keeping with this object and with others which will become apparenthereinafter, one feature of the present invention is that the rotarydrivers of the tool receptacle assigned to the rotary driving grooves inthe tool shaft are distributed around the circumference of thereceptacle bore hole in such a way that two rotary drivers are neverlocated diametrically opposite each other. The device according to theinvention has the advantage that the tool can never be inserted in thetool holder in a position in which the locking elements arranged in thetool receptacle can engage in the rotary driving grooves opening out atthe end of the tool shaft; this can be achieved without the necessity ofapplying additional locking means or the like.

It is particularly advantageous that a plurality of rotary drivinggrooves be arranged between the recesses which are closed on both sides,since the specific surface loading during the transmission of thedriving torque is reduced as the number of rotary driving groovesincreases, and the wear is accordingly decreased.

If one of the rotary driving grooves in the tool shaft is constructed soas to be deeper than the other rotary driving grooves and the respectivestrip-shaped rotary driver of the tool receptacle is constructed so asto be correspondingly higher, another advantageous step consists inproviding a conical inserting bevel at the inserting end of the toolshaft, which inserting bevel encloses an angle α with the tool axis, andin providing the front sides of the strip-shaped rotary drivers at thetool side with inserting bevels which enclose an angle β with the axisof the tool receptacle which is greater than the angle α. If, inaddition to this, the conical inserting bevel is dimensioned in such away that it cuts into the bases of the shallower rotary driving grooves,while leaving the base of the deeper rotary driving groove untouched,this arrangement provides the advantage that when introducing the toolinto the tool receptacle, a contact between the rotary driving stripsand rotary driving grooves can only be effected if the tool has firstbeen rotated relative to the tool receptacle until the highest rotarydriver lies opposite the deepest rotary driving groove. Until then,however, the smooth, i.e. "untoothed" portion of the inserting bevel ofthe tool shaft slides along the inserting bevel at the higheststrip-shaped rotary driver. Accordingly, the tool fits into thereceptacle only in this position and the operator is not irritated by acatch-like engagement of the rotary driver in the shallower rotarydriving grooves.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiment examples of the invention are shown in the drawingand expalined in more detail in the following description.

FIG. 1 is a detailed longitudinal cross-sectional view of a tool holderarranged in a drill hammer with inserted tool;

FIG. 2 is a transverse cross-sectional view taken along section lineII--II of FIG. 1;

FIG. 3 is a side view of a second embodiment of a tool shaft accordingto the present invention;

FIG. 4 is a cross-sectional view taken along section line III--III ofFIG. 3;

FIG. 5 is a side view of a third embodiment of a tool shaft according tothe present invention;

FIG. 6 is a cross-sectional view taken along section line IV--IV of FIG.5;

FIG. 7 is a side view of a fourth embodiment of a tool shaft accordingto the present invention;

FIG. 8 is a transverse cross-sectional view taken along the section lineV--V of FIG. 7;

FIG. 9 is a longitudinal cross-sectional view of a fifth embodiment of atool shaft in connection with a tool holder taken along the sectionVI--VI of FIG. 10;

FIG. 10 is a cross-sectional view taken along VII--VII of FIG. 9;

FIG. 11 is a plan view of a sixth embodiment of a tool shaft as seen inthe direction XI of FIG. 10; and

FIG. 12 is a plan view of a seventh embodiment of a tool shaft as seenin the direction of arrow XII of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A tool spindle 2 extends out of the end of the housing of a drill hammer1, which end is on the side of the workpiece and is only shown in part.The tool spindle 2 transmits a torque on the one hand and axial strokes,on the other hand, to a tool receptacle 3 which is securely connectedwith it. The tool shaft 5 of a drill 6 is inserted into the concentricreceptacle bore hole 4 of the tool holder 3. Two recesses 7 which areclosed in the axial direction at both sides are arranged at the toolshaft 5 so as to be located opposite one another on a diagonal line;assigned locking bodies 8 of the tool holder 3 are constructed as ballsto engage in the recesses 7. As can be seen in FIG. 2, the slot- orgroove-like recesses 7 have a circular-cylindrical cross-sectionalshape. The locking bodies 8 can move out of the recesses 7 of the toolshaft 5 by means of axial displacement of a sleeve 12, so that the drill6 can be removed from the tool holder 3. In addition to the recesses 7,rotary driving grooves 9 opening out at the end of the tool shaft 5 arearranged at the tool shaft 5. As can be seen in FIG. 2, the rotarydriving grooves 9 are situated so as to be offset at different anglesrelative to the recesses 7. The rotary driving grooves 9 have two planarflanks 10 which extend at least approximately radially and cooperatewith assigned surfaces of strip-shaped rotary drivers 11 which arearranged at the cylindrical inner wall of the receptacle bore hole 4 ofthe tool receptacle 3.

The rear end of the tool shaft contacts an anvil continuation 2' of thetool spindle 2 of the drill hammer, which anvil continuation 2'transmits the axial strokes. The front portion of the drill 6 located inthe front of the tool shaft 5 is constructed in a conventional manner, aview of the latter being omitted in the drawing for this reason. Aportion of the drill 6 which contains a conveying spiral for carryingaway drillings knocked loose from the drilling head adjoins a drillingshead comprising carbide cutting edges.

As can be seen from FIG. 2, one of the rotary driving grooves 9 isangularly offset by approximately 90° relative to the recesses 7, whilethe other rotary driving groove is angularly offset in an assymmetricalmanner relative to the recesses 7. It is advisable for reasons ofstability to arrange the rotary groove 9 in such a way that the flank10' transmitting the torque during operation is farther from the recess7 adjacent to it than the flank 10" is from the recess adjacent to it.

During rotation of the tool spindle 2, the torque is transmitted to thetool shaft 5 of the drill 6 via the rotary drivers 11 engaging in therotary driving grooves 9. Very favorable conditions result from theplanar flanks 10, which extend at least approximately radially, and theassigned surfaces of the strip-shaped rotary drivers 11, since theforces to be transmitted are approximately normal on the cooperatingsurfaces. The force transmission always occurs--even in the state ofadvanced wear--at surfaces and not ultimately at the edges of therecesses. The recess 7 arranged in the tool shaft 5 serve only for theaxial locking of the drill shaft in the tool receptacle 3. The stressand accordingly also the wear on the locking bodies 8, which areconstructed as balls, is very sharply reduced by means of this.

A second embodiment of the tool shaft designated here by 13 is shown inFIGS. 3 and 4 of the drawing. Recesses 7 which correspond to therecesses 7 of the first embodiment (FIGS. 1 and 2) are again arranged atthe tool shaft 13. With reference to the circumference of the tool shaft13, one rotary driving groove 14 is arranged between the two recesses 7on one side and two rotary driving grooves 15, 16 are arranged on theother side.

FIGS. 5 and 6 show an embodiment which is distinguished from thataccording to FIGS. 3 and 4 in that in the first case two rotary drivinggrooves 18, 19; 20, 21 are arranged between the recesses 7 in the toolshaft 17.

FIGS. 7 and 8 show an embodiment in which two (23, 24) driver groovesare arranged in the tool shaft 22 between the recesses 7 on one side andthree (25, 26, 27) driver grooves are arranged between the recesses 7 onthe other side in the tool shaft 22.

The advantage of the arrangement according to FIGS. 3 to 8 consists inthat the specific surface loading during the transmission of the drivingmoment is smaller the more driving grooves are present. The wear is alsosmaller to this extent.

When using a plurality of grooves in the tool shaft, it may happen that,when the tool shaft is inserted into the tool holder and the correctdrill position is sought by means of rotating to both sides, the frontside of the tool shaft and the front sides of the opposite rotarydrivers slide along one another in the manner of a catch until thecorrect inserting position is found. This not only impedes handling wheninserting a tool into the tool receptacle, but is also irritating forthe operator. A remedy is provided for this by means of an embodimentform shown in FIGS. 9 and 10.

As can be seen from FIG. 9, the tool shaft 28 comprises rotary drivinggrooves of different depths. In the shown embodiment, a rotary drivinggroove 29 having a greater depth is located opposite two rotary drivinggrooves 30, 31 of shallower depth. Strip-shaped rotary drivers 34, 35,36 are arranged at the cylindrical inner wall of the receiving bore hole33 of the tool receptacle 32. The rotary driver 34 projecting fartherforward is intended for cooperation with the rotary driving groove 29,the rotary drivers 35, 36 which project forward less far engage in therotary driving grooves 30, 31. The tool shaft 28 has a conical insertingbevel 37 at its front side. The latter encloses an angle α with the toolaxis 38. The bevel 37 is dimensioned in such a way that it cuts into thebases 39 of the rotary driving grooves 30, 31, while leaving the base 40of the rotary driving groove 29 untouched. The rotary drivers 34, 35 and36 are provided with inserting bevels 41 at their front sides on thetool side, which inserting bevels 41 enclose an angle β with the axis ofthe tool receptacle 32 coinciding with the axis 38. After the insertionof a tool shaft 28 in the receiving bore hole 33 of the tool receptacle32, the rotary driving grooves 29, 30, 31 will generally not meetexactly on the respective rotary drivers 34, 35, 36. Rather, it isnecessary to rotate the tool shaft 28 in the receiving bore hole aroundthe axis 38 until the rotary driving grooves and the rotary drivers arelocated opposite one another so as to fit in with one another and thetool can be completely inserted into the tool receptacle. Until thispoint, the tool shaft 28 is supported against the inserting bevel 41 ofthe rotary driver 34 with the edge 42 formed by its front side inconnection with the spherical outer surface area of the inserting bevel37. During the rotation of the tool, the edge 42 moves smoothly alongthe inserting bevel 41 in a sliding manner until the rotary drivinggroove 29 is located opposite the rotary driver 34 and the rotarydriving grooves 30, 31 are located opposite the rotary drivers 35, 36and the tool shaft can be completely inserted into the tool receptacle.

Two additional embodiments of a tool shaft constructed according to theinvention are shown in FIGS. 11 and 12. A coding which contains thetool-dependent data is arranged at the base of the rotary drivinggrooves 49, 50 opening out at the end of the tool shaft 48, 58 (compareXI, XII in FIG. 10). This data can refer to the type of tool--drill orchisel--, the tool dimensions--drill diameter--or the material of thetool--drill comprising heavy-duty tool steel or drill with carbideplating.

In the embodiment according to FIG. 11, the coding consists of a barcode which is painted on. In the embodiment shown in FIG. 12, the codingis formed by means of areas which are formed in the shape of stripes andcomprise different surface roughness at the base of the rotary drivinggroove 59. This surface roughness can be produced on the one hand bymeans of chemical abrasion processes or can also be producedmechanically, e.g. in the manner of file cutting.

In addition to these two examples, it is also possible to achieve thecoding by means of other geometric differences, e.g. different widths ofthe rotary driving grooves.

The coding is read by mechanical or electrical sensors, known per se,and converted into a mechanical or electrical signal which switchescorresponding mechanical or electrical couplings, or is fed, as anelectrical signal, to the electronic control unit of the hand machinetool. The selection of determined rates of rotation, striking speeds,individual striking energy, response time of the safety clutch, turningoff the drill drive or the striking mechanism, slow starting or changesof other machine parameters can be achieved by means of this.

The arrangement of the coding constitutes an advisable feature of thetools, according to the invention, since the rotary driving groovecarrying the coding or the recess carrying the coding, which recess isclosed on both sides, can always be inserted into the assigned toolreceptacle in the same angular position only when using shafts of toolswhich are constructed according to the invention. This is necessary inorder to be effective if the mechanical or electrical sensor for readingthe coding in the tool receptacle is to be used.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in atool shaft for a tool of the percussive and rotative type, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:
 1. In a device on a hand machine toolfor transmitting torque to a percussion and drilling tool having a toolshaft with an end engaged in a tool receptacle of said hand machinetool, in which at least two rotary driving grooves which open out atsaid end of said tool shaft and in which a plurality of strip-shapedrotary drivers of said tool receptacle engage in said rotary drivinggrooves and have respective assigned flanks, which are at leastapproximately planar, and in which at least one locking body is locatedin said tool receptacle and cooperate with two recesses in said toolshaft which are closed on both ends and are located diametricallyopposite one another, said tool receptacle having a receptacle borehole, the improvement wherein said rotary drivers assigned to saidrotary driving grooves in said tool shaft are distributed around saidreceptacle bore hole circumferentially in such a way that two rotarydrivers are never located diametrically opposite one another.
 2. Theimprovement as defined in claim 1, wherein at least one of said rotarydriving grooves and at least one of said rotary drivers are locatedbetween said recesses.
 3. The improvement as defined in claim 1, whereinsaid rotary driving grooves and said rotary drivers are located insubstantially one and the same axial area on said tool shaft,respectively, as said recesses and said locking bodies.
 4. In a tool,especially for percussion operation; drilling operation and percussionand drilling operation, for insertion into a bore hole of a toolreceptacle of a percussion tool, a drilling tool, or a percussion anddrilling tool, having at least two rotary driving grooves which open outat an end of a tool shaft inserted in said bore hole, said toolreceptacle having a plurality of strip-shaped rotary drivers engaged insaid rotary driving grooves provided with respective assigned flanks,which are at least approximately planar, and at least one locking bodylocated in said tool receptacle, said bore hole having a wall and a borehole axis, said strip-shaped rotary drivers extending parallel to saidbore hole axis and are located on said wall of said bore hole, theimprovement wherein said tool shaft has two recesses which are closed atboth ends and located diametrically opposite one another, and at leastone of said rotary driving grooves is located between said recesseswhich are closed at both ends, said drivers having surfaces whichcooperate with said flanks of said rotary driving grooves, at least twoof said flanks of said rotary driving grooves being circumferentiallyoffset relative to said recesses by different angular distances.
 5. Theimprovement as defined in claim 4, wherein at least one of said rotarydriving grooves has a coding which contains tool-dependent information.6. The improvement as defined in claim 5, wherein said coding comprisesa shape parameter.
 7. The improvement as defined in claim 6, whereinsaid shape parameter is a width of said rotary driving groove.
 8. Theimprovement as defined in claim 6, wherein said shape parameter is awidth and depth of said rotary driving groove.
 9. The improvement asdefined in claim 6, wherein said shape parameter is made from knurls,chamfers, grooves or other surface shapes.
 10. The improvement asdefined in claim 4, wherein at least one of said recesses has a codingwhich contains tool-dependent information.
 11. The improvement asdefined in claim 10, wherein said coding comprises a shape parameter.12. The improvement as defined in claim 11, wherein said shape parameteris a width of said rotary driving groove.
 13. The improvement as definedin claim 11, wherein said shape parameter is a width and depth of saidrotary driving groove.
 14. The improvement as defined in claim 11,wherein said shape parameter is made from knurls, chamfers, grooves orother surface shapes.
 15. The improvement as defined in claim 5, whereinsaid coding comprises a bar code.
 16. The improvement as defined inclaim 15, wherein said bar code is a painted bar code.
 17. Theimprovement as defined in claim 10, wherein said coding comprises a barcode.
 18. The improvement as defined in claim 17, wherein said bar codeis a painted bar code.
 19. In a device on a hand machine tool fortransmitting torque to a percussion tool, a drilling tool, or apercussion and drilling tool having a tool shaft with an end engaged ina tool receptacle of said hand machine tool, in which at least tworotary driving grooves which open out at said end of said tool shaft andin which a plurality of strip-shaped rotary drivers of said toolreceptacle engage in said rotary driving grooves and have respectiveassigned flanks, which are at least approximately planar, and in whichat least one locking body is located in said tool receptacle andcooperate with two recesses in said tool shaft which are closed on bothends and are located diametrically opposite one another, said toolreceptacle having a receptacle bore hole, the improvement wherein saidrotary drivers assigned to said rotary driving grooves in said toolshaft are distributed around said receptacle bore hole circumferentiallyin such a way that two rotary drivers are never located diametricallyopposite one another, at least one of said rotary driving grooves and atleast one of said rotary drivers being located between said recesseswhich are closed at both of said ends, the number of said rotary drivinggrooves located between said two recesses on one side of said tool shaftbeing greater than the number of said rotary driving grooves located onthe other side of said tool shaft.
 20. In a device on a hand machinetool for transmitting torque to a percussion tool, a drilling tool, or apercussion and drilling tool having a tool shaft with an end engaged ina tool receptacle of said hand machine tool, in which at least tworotary driving grooves which open out at said end of said tool shaft andin which a plurality of strip-shaped rotary drivers of said toolreceptacle engage in said rotary driving grooves and have respectiveassigned flanks, which are at least approximately planar, and in whichat least one locking body is located in said tool receptacle andcooperate with two recesses in said tool shaft which are closed on bothends and are located diametrically opposite one another, said toolreceptacle having a receptacle bore hole, the improvement wherein saidrotary drivers assigned to said rotary driving grooves in said toolshaft are distributed around said receptacle bore hole circumferentiallyin such a way that two rotary drivers are never located diametricallyopposite one another, each of said rotary driving grooves in said toolshaft having a different width from that of another of said rotarydriving grooves and each of said rotary drivers having a different widthfrom that of another of said rotary drivers.
 21. In a device on a handmachine tool for transmitting torque to a percussion tool, a drillingtool, or a percussion and drilling tool having a tool shaft with an endengaged in a tool receptacle of said hand machine tool, in which atleast two rotary driving grooves which open out at said end of said toolshaft and in which a plurality of strip-shaped rotary drivers of saidtool receptacle engage in said rotary driving grooves and haverespective assigned flanks, which are at least approximately planar, andin which at least one locking body is located in said tool receptacleand cooperate with two recesses in said tool shaft which are closed onboth ends and are located diametrically opposite one another, said toolreceptacle having a receptacle bore hole, the improvement wherein saidrotary drivers assigned to said rotary driving grooves in said toolshaft are distributed around said receptacle bore hole circumferentiallyin such a way that two rotary drivers are never located diametricallyopposite one another, each of said rotary driving grooves in said toolshaft having a different depth from that of another of said rotarydriving grooves and each of said rotary drivers having a different depthfrom that of another of said rotary drivers.
 22. In a device on a handmachine tool for transmitting torque to a percussion tool, a drillingtool, or a percussion and drilling tool having a tool shaft with an endengaged in a tool receptacle of said hand machine tool, in which atleast two rotary driving grooves which open out at said end of said toolshaft and in which a plurality of strip-shaped rotary drivers of saidtool receptacle engage in said rotary driving grooves and haverespective assigned flanks, which are at least approximately planar, andin which at least one locking body is located in said tool receptacleand cooperate with two recesses in said tool shaft which are closed onboth ends and are located diametrically opposite one another, said toolreceptacle having a receptacle bore hole, the improvement wherein saidrotary drives assigned to said rotary driving grooves in said tool shaftare distributed around said receptacle bore hole circumferentially insuch a way that two rotary drivers are never located diametricallyopposite one another, one of said rotary driving grooves in said toolshaft being deeper than the other ones of said rotary driving groovesand having a deeper groove bottom while said other rotary drivinggrooves have shallower groove bottoms and the respective strip-shapedrotary driver of said tool receptacle being constructed so as to becorrespondingly higher than the other of said rotary drivers.
 23. Theimprovement as defined in claim 22, wherein said tool shaft has aninserting end and a tool axis and said inserting end has a conicalinserting bevel which forms an angle α with said tool axis, saidstrip-shaped rotary drivers having facing ends directed toward saidconical inserting bevel, said facing ends of said strip-shaped rotarydrivers having inserting bevels which form an angle β with alongitudinal axis of said tool receptacle running in the same directionas said tool axis of said tool shaft, said angle β being greater thansaid angle α, and said conical inserting bevel being dimensioned in sucha way that said conical inserting bevel engages said shallower groovebottoms while leaving said deeper groove bottoms untouched.
 24. In atool, especially for percussion operation, drilling operation andpercussion and drilling operation for insertion into a bore hole of atool receptacle of a percussion tool, a drilling tool, or a percussionand drilling tool, having at least two rotary driving grooves which openout at an end of a tool shaft inserted in said bore hole, said toolreceptacle having a plurality of strip-shaped rotary drivers engaged insaid rotary driving grooves provided with respective assigned flanks,which are at least approximately planar, and at least one locking bodylocated in said tool receptacle, said bore hole having a wall and a borehole axis, said strip-shaped rotary drivers extending parallel to saidbore hole axis and are located on said wall of said bore hole, theimprovement wherein said tool shaft has two recesses which are closed atboth ends and located diametrically opposite one another, and at leastone of said rotary driving grooves is located between said recesseswhich are closed at both ends, said drivers having surfaces whichcooperate with said flanks of said rotary driving grooves, at least twoof said flanks of said rotary driving grooves being circumferentiallyoffset relative to said recesses by different angular distances, atleast one of said rotary driving grooves for at least one of said rotarydrivers being located between said recesses which are closed at both ofsaid ends, the number of said rotary driving grooves located betweensaid two recesses on one side of said tool shaft being greater than thenumber of said rotary driving grooves located on the other side of saidtool shaft.
 25. In a tool, especially for percussion operation, drillingoperation and percussion and drilling operation for insertion into abore hole of a tool receptacle of a percussion tool, a drilling tool, ora percussion and drilling tool, having at least two rotary drivinggrooves which open out at an end of a tool shaft inserted in said borehole, said tool receptacle having a plurality of strip-shaped rotarydrivers engaged in said rotary driving grooves provided with respectiveassigned flanks, which are at least approximately planar, and at leastone locking body located in said tool receptacle, said bore hole havinga wall and a bore hole axis, said strip-shaped rotary drivers extendingparallel to said bore hole axis and are located on said wall of saidbore hole, the improvement wherein said tool shaft has two recesseswhich are closed at both ends and located diametrically opposite oneanother, and at least one of said rotary driving grooves is locatedbetween said recesses which are closed at both ends, said drivers havingsurfaces which cooperate with said flanks of said rotary drivinggrooves, at least two of said flanks of said rotary driving groovesbeing circumferentially offset relative to said recesses by differentangular distances, and at least one of said rotary driving grooves islocated between said recesses which are closed at both ends, said rotarydriving grooves being distributed circumferentially around said toolshaft so that one of said rotary driving grooves is never diametricallyopposite another of said rotary driving grooves, each of said rotarydriving grooves in said tool shaft having a different width from that ofanother of said rotary driving grooves.
 26. In a tool, especially forpercussion operation, drilling operation and percussion and drillingoperation for insertion into a bore hole of a tool receptacle of apercussion tool, a drilling tool, or a percussion and drilling tool,having at least two rotary driving grooves which open out at an end of atool shaft inserted in said bore hole, said tool receptacle having aplurality of strip-shaped rotary drivers engaged in said rotary drivinggrooves provided with respective assigned flanks, which are at leastapproximately planar, and at least one locking body located in said toolreceptacle, said bore hole having a wall and a bore hole axis, saidstrip-shaped rotary drivers extending parallel to said bore hole axisand are located on said wall of said bore hole, the improvement whereinsaid tool shaft has two recesses which are closed at both ends andlocated diametrically opposite one another, and at least one of saidrotary driving grooves is located between said recesses which are closedat both ends, said drivers having surfaces which cooperate with saidflanks of said rotary driving grooves, at least two of said flanks ofsaid rotary driving grooves being circumferentially offset relative tosaid recesses by different angular distances, and at least one of saidrotary driving grooves is located between said recesses which are closedat both ends, said rotary driving grooves being distributedcircumferentially around said tool shaft so that one of said rotarydriving grooves is never diametrically opposite another of said rotarydriving grooves, each of said rotary driving grooves in said tool shafthaving a different depth from that of another of said rotary drivinggrooves.
 27. In a tool, especially for percussion operation, drillingoperation and percussion and drilling operation, for insertion into abore hole of a tool receptacle of a percussion tool, a drilling tool, ora percussion and drilling tool, having at least two rotary drivinggrooves which open out at an end of a tool shaft inserted in said borehole, said tool receptacle having a plurality of strip-shaped rotarydrivers engaged in said rotary driving grooves provided with respectiveassigned flanks, which are at least approximately planar, and at leastone locking body located in said tool receptacle, said bore hole havinga wall and a bore hole axis, said strip-shaped rotary drivers extendingparallel to said bore hole axis and are located on said wall of saidbore hole, the improvement wherein said tool shaft has two recesseswhich are closed at both ends and located diametrically opposite oneanother, and at least one of said rotary driving grooves is locatedbetween said recesses which are closed at both ends, said drivers havingsurfaces which cooperate with said flanks of said rotary drivinggrooves, at least two of said flanks of said rotary driving groovesbeing circumferentially offset relative to said recesses by differentangular distances, and at least one of said rotary driving grooves islocated between said recesses which are closed at both ends, said rotarydriving grooves being distributed circumferentially around said toolshaft so that one of said rotary driving grooves is never diametricallyopposite another of said rotary driving grooves, one of said rotarydriving grooves in said tool shaft being deeper than the other ones ofsaid rotary driving grooves and having a deeper groove bottom while saidother rotary driving grooves have shallower groove bottoms.